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You searched for: creator:"Ofir"
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[audio]Tza'aTzu'im - Ofir
Ofir's TzaaTzuim sessions featuring Hadas.
Keywords: Ofir's Tzaatzuim; LowLevels; Noise Problems
Downloads: 276
[audio]Ofir - Hey You , Come Here [birdsong008] - Ofir
recorded into a korg d-16 using vocals,a yamaha S8 synthesizer, drums,guitar and melodica all songs in hebrew
Downloads: 7,193
[audio]no. 14 - Ofir Klemperer
*made in 2008 by ofir klemperer. ofir klemperer wrote the hebrew music compositions, and plays -toy / acoustic / electronic / analog instruments, record, overdub, edit, and mix. seconds \ days. *all paintings were drawn by Amnon Yuhas.
Downloads: 43
[audio]hey you, come here - Ofir Klemperer
"hey you, come here" is a collection out of the variety of documented music which was found inside the beautiful but threatening to burst head of Ofir Klemperer. six songs in hebrew and one instrumental piece, were chosen to create this album which Ofir claims to be an introduction album. The Tunes are complex and unusual, arrangments are colorful , variety of sounds and textures. Some times the touch is electronic, sometimes acoustic and sometimes something else, and always typical to ofir wit...
Downloads: 40
[audio]no. 13 - Ofir Klemperer
this is an extrordinary mixture of different musical impulses. the music of ofir klemperer is dynamic, challenging, impulsive, electric, eclectic, weird and astonishing – always with a strong feeling within and slightly disturbing. this is contemporary shit kicking your ass – you can’t hide. physical! *made in 2008 by ofir klemperer. ofir klemperer wrote the hebrew music compositions, and plays -toy / acoustic / electronic / analog instruments, record, overdub, edit, and mix...
Downloads: 36
[audio]Safe Place - Ofir Klemperer
Ofir Klemperer and The Den Haag All $tar$ on various occasions. Studio Album
Downloads: 13
[texts]An Algorithm For Photometric Identification Of Transiting Circumbinary Planets - Aviv Ofir
Transiting planets manifest themselves by a periodic dimming of their host star by a fixed amount. On the other hand, light curves of transiting circumbinary (CB) planets are expected to be neither periodic nor to have a single depth while in transit. These propertied make the popular transit finding algorithm BLS almost ineffective so a modified version of BLS for the identification of CB planets was developed - CB-BLS...
Downloads: 2
[texts]Graded Embeddings of Finite Dimensional Simple Graded Algebras - Ofir David
Let A,B be finite dimensional G-graded algebras over an algebraically closed field K with char(K)=0, where G is an abelian group, and let Id_G(A) be the set of graded identities of A (res. Id_G(B)). We show that if A,B are G-simple then there is a graded embedding of A in B iff Id_G(B) is contained in Id_G(A). We also give a weaker generalization for the case where A is G-semisimple and B is arbitrary.
Downloads: 1
[texts]Two pairs of interacting EBs towards the LMC in the OGLE database - Aviv Ofir
A single point source on the OGLE LMC database shows the characteristics of two superimposed eclipsing binaries (EBs). The two EBs happen to have periods very close to the 3:2 resonance. The telescope's small PSF and the apparent resonance between the two EBs raises the suspicion that this is not chance alignment but rather a compact hierarchical system of two pairs of interacting EBs in 3:2 resonance.
Downloads: 2
[audio]Safe Place - Ofir Klemperer
Ofir Klemperer and the Den Haag all stars - "Safe Place"
Keywords: Ofir; LowLevels; Noise Problems
Downloads: 268
[texts]Identifying Transiting Circumbinary Planets - A. Ofir
Transiting planets manifest themselves by a periodic dimming of their host star by a fixed amount. On the other hand, light curves of transiting circumbinary (CB) planets are expected to be neither periodic nor to have a single depth while in transit, making BLS [Kovacs et al. 2002] almost ineffective. Therefore, a modified version for the identification of CB planets was developed - CB-BLS. We show that using CB-BLS it is possible to find CB planets in the residuals of light curves of eclipsing...
Downloads: 9
[audio]ofir gold - ofir gold

Keywords: U
Downloads: 35
[audio]Reference Thoughts - Ofir Klemperer
a piece for an ensemble. Performed by Ensemble62
Keywords: Ofir Klemperer; Experimental music; Ensemble Modelo 62
Downloads: 35
[audio]no.13 - Ofir Klemperer
Ofir Klemperer - no.13 this is an extrordinary mixture of different musical impulses. the music of ofir klemperer is dynamic, challenging, impulsive, electric, eclectic - always with a strong feeling within and lightly disturbing. this is contemporary shit kicking your ass - you can't hide. physical! *made in 2008 by ofir klemperer. ofir klemperer wrote the hebrew music compositions, and plays -toy / acoustic / electronic / analog instruments, record, overdub, edit, and mix...
Keywords: headphonica; hpcd075; ofir klemperer
Downloads: 1,225
[other]No. 14 - Ofir Klemperer

Downloads: 20
[audio]no.14 - Ofir Klemperer
*made in 2008 by ofir klemperer. ofir klemperer wrote the hebrew music compositions, and plays -toy / acoustic / electronic / analog instruments, record, overdub, edit, and mix. seconds \ days. *all paintings were drawn by Amnon Yuhas.
Keywords: Ofir Klemperer; no.14; hpcd059; headphonica
Downloads: 941
[texts]On regular G-grading - Eli Aljadeff
Let A be an associative algebra over an algebraically closed field F of characteristic zero and let G be a finite abelian group. Regev and Seeman introduced the notion of a regular G-grading on A, namely a grading A= {\Sigma}_{g in G} A_g that satisfies the following two conditions: (1) for every integer n>=1 and every n-tuple (g_1,g_2,...,g_n) in G^n, there are elements, a_i in A_{g_i}, i=1,...,n, such that a_1*a_2*...*a_n != 0...
Downloads: 2
[texts]Improving Perceptual Color Difference using Basic Color Terms - Ofir Pele
We suggest a new color distance based on two observations. First, perceptual color differences were designed to be used to compare very similar colors. They do not capture human perception for medium and large color differences well. Thresholding was proposed to solve the problem for large color differences, i.e. two totally different colors are always the same distance apart. We show that thresholding alone cannot improve medium color differences...
Downloads: 1
[texts]Infinite matrices may violate the associative law - Ofir E. Alon
The momentum operator for a particle in a box is represented by an infinite order Hermitian matrix $P$. Its square $P^2$ is well defined (and diagonal), but its cube $P^3$ is ill defined, because $P P^2\neq P^2 P$. Truncating these matrices to a finite order restores the associative law, but leads to other curious results.
Downloads: 2
[texts]Sensitivities of the Proton-Nucleus Elastical Scattering Observables of 6He and 8He at Intermediate Energies - Stephen P. Weppner
We investigate the use of proton-nucleus elastic scattering experiments using secondary beams of 6He and 8He to determine the physical structure of these nuclei. The sensitivity of these experiments to nuclear structure is examined by using four different nuclear structure models with different spatial features using a full-folding optical potential model. The results show that elastic scattering at intermediate energies (
Downloads: 3
[texts]Low Density Lattice Codes - Naftali Sommer
Low density lattice codes (LDLC) are novel lattice codes that can be decoded efficiently and approach the capacity of the additive white Gaussian noise (AWGN) channel. In LDLC a codeword x is generated directly at the n-dimensional Euclidean space as a linear transformation of a corresponding integer message vector b, i.e., x = Gb, where H, the inverse of G, is restricted to be sparse. The fact that H is sparse is utilized to develop a linear-time iterative decoding scheme which attains, as demo...
[texts]Pathway from condensation via fragmentation to fermionization of cold bosonic systems - Ofir E. Alon
For small scattering lengths, cold bosonic atoms form a condensate the density profile of which is smooth. With increasing scattering length, the density {\it gradually} acquires more and more oscillations. Finally, the number of oscillations equals the number of bosons and the system becomes {\it fermionized}. On this pathway from condensation to fermionization intriguing phenomena occur, depending on the shape of the trap...
[texts]Signal Codes - Ofir Shalvi
Motivated by signal processing, we present a new class of channel codes, called signal codes, for continuous-alphabet channels. Signal codes are lattice codes whose encoding is done by convolving an integer information sequence with a fixed filter pattern. Decoding is based on the bidirectional sequential stack decoder, which can be implemented efficiently using the heap data structure. Error analysis and simulation results indicate that signal codes can achieve low error rate at approximately 1...
Downloads: 1
[texts]Searching For Transiting Circumbinary Planets in CoRoT and Ground-Based Data Using CB-BLS - A. Ofir
Aims. We search for transiting circumbinary (CB) planets around eclipsing binaries (EBs). Methods. CB-BLS is a recently-introduced algorithm for the detection of transiting CB planets around EBs.We describe progress in search sensitivity, generality and capability of CB-BLS, and detection tests of CB-BLS on simulated data. We also describe an analytical approach for the determination of CB-BLS detection limits, and a method for the correct detrending of intrinsically-variable stars...
Downloads: 2
[texts]Formation of dynamical Schrödinger cats in low-dimensional ultracold attractive Bose gases - Alexej I. Streltsov
Dynamical Schr\"odinger cats can be formed when a one-dimensional attractive Bose-gas cloud is scattered off a potential barrier. Once formed, these objects are stable in time. The phenomenon and its mechanism -- transformation of kinetic energy to internal energy of the scattered atomic cloud -- are obtained by solving the time-dependent many-boson Schr\"odinger equation. Implications are discussed.
Downloads: 2
[texts]General variational many-body theory with complete self-consistency for trapped bosonic systems - Alexej I. Streltsov
In this work we develop a complete variational many-body theory for a system of $N$ trapped bosons interacting via a general two-body potential. In this theory both the many-body basis functions {\em and} the respective expansion coefficients are treated as variational parameters. The optimal variational parameters are obtained {\em self-consistently} by solving a coupled system of non-eigenvalue -- generally integro-differential -- equations to get the one-particle functions and by diagonalizin...
Downloads: 1
[texts]Zoo of quantum phases and excitations of cold bosonic atoms in optical lattices - Ofir E. Alon
Quantum phases and phase transitions of weakly- to strongly-interacting bosonic atoms in deep to shallow optical lattices are described by a {\it single multi-orbital mean-field approach in real space}. For weakly-interacting bosons in 1D, the critical value of the superfluid to Mott insulator (MI) transition found is in excellent agreement with {\it many-body} treatments of the Bose-Hubbard model...
Downloads: 1
[texts]On-top fragmentation stabilizes atom-rich attractive Bose-Einstein condensates - Lorenz S. Cederbaum
It is well known that attractive condensates do not posses a stable ground state in three dimensions. The widely used Gross-Pitaevskii theory predicts the existence of metastable states up to some critical number $N_{\mathrm{cr}}^{\mathrm{GP}}$ of atoms. It is demonstrated here that fragmented metastable states exist for atom numbers well above $N_{\mathrm{cr}}^{\mathrm{GP}}$. The fragments are strongly overlapping in space...
Downloads: 3
[texts]A novel general mapping for bosonic and fermionic operators in Fock space - Alexej I. Streltsov
In this paper we provide a novel and general way to construct the result of the action of any bosonic or fermionic operator represented in second quantized form on a state vector, without resorting to the matrix representation of operators and even to its elements. The new approach is based on our proposal to compactly enumerate the configurations (i.e., determinants for fermions, permanents for bosons) which are the elements of the state vector...
Downloads: 2
[texts]Formation and dynamics of many-boson fragmented states in attractive one-dimensional ultra-cold gases - Alexej I. Streltsov
Dynamics of attractive ultra-cold bosonic clouds in one dimension are studied by solving the many-particle time-dependent Schr\"odinger equation. The initially coherent wave-packet can dynamically dissociate into two parts when its energy exceeds a threshold value. Noticeably, the time-dependent Gross-Pitaevskii theory applied to the same initial state does not show up the splitting. We call the split object {\it fragmenton}...
Downloads: 2
[texts]Coupled-Cluster Theory for Systems of Bosons in External Traps - Lorenz S. Cederbaum
A coupled-cluster approach for systems of $N$ bosons in external traps is developed. In the coupled-cluster approach the exact many-body wavefunction is obtained by applying an exponential operator $\exp{T}$ to the ground configuration $|\phi_0>$. The natural ground configuration for bosons is, of course, when all reside in a single orbital. Because of this simple structure of $|\phi_0>$, the appearance of excitation operators $T=\sum_{n=1}^N T_n$ for bosons is much simpler than for fermions...
Downloads: 2
[texts]Death of soliton trains in attractive Bose-Einstein condensates - Alexej I. Streltsov
Experiments on ultra-cold attractive Bose-Einstein Condensates (BECs) have demonstrated that at low dimensions atomic clouds can form localized objects, propagating for long times without significant changes in their shapes and attributed to bright matter-wave solitons, which are coherent objects. We consider the dynamics of bright soliton trains from the perspective of many-boson physics. The fate of matter-wave soliton trains is actually to quickly loose their coherence and become macroscopica...
Downloads: 1
[texts]Many-body theory for systems with particle conversion: Extending the multiconfigurational time-dependent Hartree method - Ofir E. Alon
We derive a multiconfigurational time-dependent Hartree theory for systems with particle conversion. In such systems particles of one kind can convert to another kind and the total number of particles varies in time. The theory thus extends the scope of the available and successful multiconfigurational time-dependent Hartree methods -- which were solely formulated for and applied to systems with a fixed number of particles -- to new physical systems and problems...
Downloads: 3
[texts]On interacting fermions and bosons with definite total momentum - Ofir E. Alon
Any {\it exact} eigenstate with a definite momentum of a many-body Hamiltonian can be written as an integral over a {\it symmetry-broken} function $\Phi$. For two particles, we solve the problem {\it exactly} for all energy levels and any inter-particle interaction. Especially for the ground-state, $\Phi$ is given by the simple Hartree-Fock/Hartree ansatz for fermions/bosons. Implications for several and many particles as well as a numerical example are provided.
Downloads: 7
[texts]Role of excited states in the splitting dynamics of interacting Bose-Einstein condensates when ramping-up a barrier - Alexej I. Streltsov
An essentially-exact approach to compute the wavefunction in the time-dependent many-boson Schr\"odinger equation is derived and employed to study accurately the process of splitting a trapped condensate when ramping-up a barrier such that a double-well is formed. We follow the role played by many-body excited states during the splitting process. Among others, a 'counter-intuitive' regime is found in which the evolution of the condensate when the barrier is ramped-up sufficiently slow {\it is no...
[texts]Cold atoms in real-space optical lattices - Ofir E. Alon
Cold atoms in optical lattices are described in {\it real space} by multi-orbital mean-field Ans\"atze. In this work we consider four typical systems: (i) spinless identical bosons, (ii) spinor identical bosons (iii), Bose-Bose mixtures, and (iv) Bose-Fermi mixtures and derive in each case the corresponding multi-orbital mean-field energy-functional and working equations. The notions of {\it dressed} Wannier functions and Wannier spinors are introduced and the equations defining them are present...
[texts]The multi-configurational time-dependent Hartree method for bosons: Many-body dynamics of bosonic systems - Ofir E. Alon
The evolution of Bose-Einstein condensates is amply described by the time-dependent Gross-Pitaevskii mean-field theory which assumes all bosons to reside in a single time-dependent one-particle state throughout the propagation process. In this work, we go beyond mean-field and develop an essentially-exact many-body theory for the propagation of the time-dependent Schr\"odinger equation of $N$ interacting identical bosons...
[texts]Phase separations of bosonic mixtures in optical lattices from macroscopic to microscopic scales - Ofir E. Alon
Mixtures of cold bosonic atoms in optical lattices undergo phase separations on different length scales with increasing inter-species repulsion. As a general rule, the stronger the intra-species interactions, the shorter is this length scale. The wealth of phenomena is documented by illustrative examples on both superfluids and Mott-insulators.
[texts]Exact quantum dynamics of bosons with finite-range time-dependent interactions of harmonic type - Axel U. J. Lode
The exactly solvable quantum many-particle model with harmonic one- and two-particle interaction terms is extended to include time-dependency. We show that when the external trap potential and finite-range interparticle interaction have a time-dependency the exact solutions of the corresponding time-dependent many-boson Schr\"odinger equation are still available. We use these exact solutions to benchmark the recently developed multiconfigurational time-dependent Hartree method for bosons (MCTDHB...
Downloads: 2
[texts]Fragmented Many-Body states of definite angular momentum and stability of attractive 3D Condensates - Marios C. Tsatsos
A three dimensional attractive Bose-Einstein Condensate (BEC) is expected to collapse, when the number of the particles $N$ in the ground state or the interaction strength $\lambda_0$ exceeds a critical value. We study systems of different particle numbers and interaction strength and find that even if the overall ground state is collapsed there is a plethora of fragmented excited states that are still in the metastable region...
Downloads: 2
[texts]Reduced density matrices and coherence of trapped interacting bosons - Kaspar Sakmann
The first- and second-order correlation functions of trapped, interacting Bose-Einstein condensates are investigated numerically on a many-body level from first principles. Correlations in real space and momentum space are treated. The coherence properties are analyzed. The results are obtained by solving the many-body Schr\"odinger equation. It is shown in an example how many-body effects can be induced by the trap geometry...
Downloads: 1
[texts]Universality of Fragmentation in the Schrödinger Dynamics of Bosonic Josephson Junctions - Kaspar Sakmann
The many-body Schr\"odinger dynamics of a one-dimensional bosonic Josephson junction is investigated for up to ten thousand bosons and long times. The initial states are fully condensed and the interaction strength is weak. We report on a universal fragmentation dynamics on the many-body level: systems consisting of different numbers of particles fragment to the same value at constant mean-field interaction strength...
Downloads: 2
[texts]Accurate multi-boson long-time dynamics in triple-well periodic traps - Alexej I. Streltsov
To solve the many-boson Schr\"odinger equation we utilize the Multiconfigurational time-dependent Hartree method for bosons (MCTDHB). To be able to attack larger systems and/or to propagate the solution for longer times, we implement a parallel version of the MCTDHB method thereby realizing the recently proposed [Streltsov {\it et al.} arXiv:0910.2577v1] novel idea how to construct efficiently the result of the action of the Hamiltonian on a bosonic state vector...
Downloads: 3
[texts]Number fluctuations of cold spatially split bosonic objects - Kaspar Sakmann
We investigate the number fluctuations of spatially split many-boson systems employing a theorem about the maximally and minimally attainable variances of an observable. The number fluctuations of many-boson systems are given for different numbers of lattice sites and both mean-field and many-body wave functions. It is shown which states maximize the particle number fluctuations, both in lattices and double-wells...
Downloads: 2
[texts]Continuous configuration-interaction for condensates in a ring - Ofir E. Alon
A continuous configuration-interaction approach for condensates in a ring is introduced. In its simplest form this approach utilizes for attractive condensates the Gross-Pitaevskii symmetry-broken solution and arrives at a ground-state of correct symmetry. Furthermore, the energy found is {\it lower} than the Gross-Pitaevskii one and, with increasing number of particles and/or strength of inter-particle interaction, is even {\it lower} than that accessed by tractable diagonalization of the many-...
Downloads: 2
[texts]Dynamics and symmetries of a repulsively bound atom pair in an infinite optical lattice - Andreas Deuchert
We investigate the dynamics of two bosons trapped in an infinite one-dimensional optical lattice potential within the framework of the Bose-Hubbard model and derive an exact expression for the wavefunction at finite time. As initial condition we chose localized atoms that are separated by a distance of $d$ lattice sites and carry a center of mass quasi-momentum. An initially localized pair ($d=0$) is found to be more stable as quantified by the pair probability (probability to find two atoms at ...
Downloads: 2
[texts]Two trapped particles interacting by a finite-ranged two-body potential in two spatial dimensions - Rostislav A. Doganov
We examine the problem of two particles confined in an isotropic harmonic trap, which interact via a finite-ranged Gaussian-shaped potential in two spatial dimensions. We derive an approximative transcendental equation for the energy and study the resulting spectrum as a function of the interparticle interaction strength. Both the attractive and repulsive systems are analyzed. We study the impact of the potential's range on the ground-state energy...
Downloads: 2
[texts]How does an interacting many-body system tunnel through a potential barrier to open space? - Axel U. J. Lode
The tunneling process in a many-body system is a phenomenon which lies at the very heart of quantum mechanics. It appears in nature in the form of alpha-decay, fusion and fission in nuclear physics, photoassociation and photodissociation in biology and chemistry. A detailed theoretical description of the decay process in these systems is a very cumbersome problem, either because of very complicated or even unknown interparticle interactions or due to a large number of constitutent particles...
Downloads: 4
[texts]Excitation spectra of fragmented condensates by linear response: General theory and application to a condensate in a double-well potential - Julian Grond
Linear response of simple (i.e., condensed) Bose-Einstein condensates is known to lead to the Bogoliubov- de Gennes equations. Here, we derive linear response for fragmented Bose-Einstein condensates, i.e., for the case where the many-body wave function is not a product of one, but of several single-particle states (orbitals). Our approach is based on the number-conserving variational time-dependent mean field theory [O...
[texts]Exact ground state of finite Bose-Einstein condensates on a ring - Kaspar Sakmann
The exact ground state of the many-body Schr\"odinger equation for $N$ bosons on a one-dimensional ring interacting via pairwise $\delta$-function interaction is presented for up to fifty particles. The solutions are obtained by solving Lieb and Liniger's system of coupled transcendental equations for finite $N$. The ground state energies for repulsive and attractive interaction are shown to be smoothly connected at the point of zero interaction strength, implying that the \emph{Bethe-ansatz} ca...
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